Telephone-exchange system.



H. P. CLAUSEN. TELEPHONE EXCHANGE SYSTEM.

APPucATmu FILED 001.21.1915.

Patented July 10, 1917.

Henry C/aus en.

A ffy.

HENRY P. GLAUSEN, or MOUNT- VERNON, NEW YORK, ASSIGNOR, 'BY EsNE 'AssIGN I MENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A QORPORATIONOF= NEW YORK.

' phone-Exchange Systems, of which the following is a full, clear, concise, and'exact description.

This invention relates to improvements in telephone exchange systems, and has for its principal object to provide means for ren-.

dering more eflicient and satisfactory service in the handling of calls that are abandoned by a calling subscriber before the subscriber who is being called has answered.

In accordance with one feature of this in- Vention, the link circuits at a telephone switchboard are equipped with a retarder circuit-controlling device which delays the operation of disconnect signals until a predetermined time after an incompleted call has been abandoned by a calling subscriber.

According to another feature of this invention, characteristic signaling effects are produced on the supervisory signals at certain stages in the operation of the system to indicate to the operator immediately the condition of the connections.

This invention is illustrated diagrammatically in the drawing, in which complete station and switchboard equipment for two central-energy subscribers telephone lines, of a wellknown type, are respectively indicated by the numerals 1 and2. A link circuit, indicated at a switchboard position 3, adapted to connect the stations 1 and 2 for communication, is equipped with a thermal relay suitable for illustrating the features of this invention.

In describing the operation of this sys tem, let it be assumed that a subscriber at the station 1 desires to communicate with a subscriber at the station 2. Removal of the receiver from the switch-hook at station 1 causes a line lamp 5 to be lighted through the operation of a line relay 4, in response to which an operator at the position 3 lnserts an answering plug 9 of the link conductor in the jack 7 of this calling line. The energization of a cut-off relay 6,11sten1ng relay 17 and a control relay 12 now take place over associated paths which may be traced from earth, winding of relay 6, signal cir- TELEPHONE-EXCi-IANGE SYSTEM.

Specification of Letters Patent. Patente gl J fl flby glqj Application filed October 21,1915. l

'circuit completed through the signal-con- Seria1No.57,069- H I cuit contacts 8 and 10 of "jack plug 5 5 9, respectively, thence branching, first, way of conductor 11 andthe windingot e lay 12 to earth through the battery "60, and? the relay 17, conductor iaeonmcfl 2.8012' a 6 0 relay 30 through the battery "to" This answering connection also iender a pervisory relay 20 resp' ns'ive' tb'tjalkihg rent, which is supplied from bat ry60 through its windings, weathe man.er talk 6%" ing conductors to the telephone instrlir'n at station 1. Although no operato'rfste F phone set is shown in thedr'awing; it wi'lljbe understood that the listening relay"'17 is for the purpose of including such a telephone set with the talking conductorsofthis eon-i nection. In response to the request of the calling subscriber, the operator nmvinsercsj a calling plug 32 of the link circuit '-'ina'- jack 34 of the line 2. A second control ref lay 30 and a cut-off relay'61, thelatte'r"associated with the line 2, arelther'eby energized by current from the battery 60 over a-series' tacts 31 and 33 of the plug32 and the-jack: 34, respectively. The cut-ofi relay 6'1. dis; connects its associated line relay from theline circuit 2 and the contacts 28"*o'f"relay 30 disconnect the listening'relay 17',"there'loy" disconnecting the operators telephone (not shown) from thetalking"circuits-oi this connection. The relay 30 'also clo'ses a circuit through its contacts 29to'*iiiclude "a supervisory signal 36 on the battery -60," the further circuits ofwhich may be traced; from contacts 37 of a supervisory relay" 38, conductor 39, contacts 41 of'supervisory master relay 40, conductor 42, cori'tacts*46 of'a 'ringi' ing relay 45, and contacts 51TH atrip relay 50 to earth. In order to 'ringthe fb'el l'flat" station 2, the operator now lmomentarily de-f presses a key 53 thereby completing a'eimu'it for the energization of relays 40 and' 45g; This circuit may be traced from the' bat'tery 60, contacts 22 of the relay 20, the hand winding of the relay 4 0, cOnductorA l the winding of relay 45, coriductor 52;, earth through the key Tha -cont members 48 and 49 of relay open 'e p side of the callingendofjthe link"'c'irjc uit' toward the station 1, and connecta source of ounded ringing currentfnot shown); indicated as feeding through the trip}: lay

80 v for the supervisory'lamps 15 and 36. Al-v 50, to the line circuit of the station 2 The closing of contacts .47 of relay 45 substitute an earthconnection through the contacts 51 of the trip relay 50 for the earth connection through the key 53 to retain the relays 40 and 45 after the key 53 has been released.

The separation of contacts 46 of the relay.

45 opens the circuit of the supervisory lamp 36, and the separation of contacts 21 of the supervisory relay 20 opens the circuit of the supervisory lamp Therefore, both of the supervisory lamps are extinguished during the period ringing current is being,,* applied to the line circuit'ofthe called subscriber.

- the receiver on the switch-hook. Thisr'e 56 of the thermal relay 55, conductor 42,

ing current 2 and reestablish the talking circuit of the With the circuits'inthe position just -in-. dicated, that is, relays 6, '12, 20, 30, 61, 40

and energized, let-it be" assumed that; the subscriber at station 1 decides not to wait for an answer from station 2, and accordingly abandons the. call by replacing sults in cessation of talking current through the instrument at station 1, thereby deenergizing the supervisory relay 20.- The separation of contacts 22 of the relay 20 releases the ringing relay 45 to disconnect the ringfrom the line circuit. of station link' conductors; and also prepares a circuit through the contacts 46 of the latter relay though the separation of the contacts 22 of relay 20 permits the release of the relay 45,

the relay 40 is influenced byits copper secondary to remain energized until the contacts 23 of relay 20 are closed to complete a locking circuit from" battery 60, theleft hand winding of relay 40, contacts 43 of this relay, and'contac'ts 130i relay 12 to earth;

The contacts 41 of relay 40 being retained separated, the winding 56 of the thermal re lay is energized by current jointly supplied through the circuits ofthe supervisory lamps 15 and 36. One of these circuits includes the battery '60, contacts '14 of the relay 12, the lamp 1-5, contacts 21 of the relay 20. and conductor 58 to a junction with conductor 39; the other circuit includes battery 60, contacts 29 of the relay 30, the lamp 36, contacts 37 of the relay 38, and conductor 39 to the junction formed with conductor 58. From this junction the current from each path completes'circuit through the winding contacts 46 of the relay 45, and contacts 51 of the relay 50 to earth. The supervisory lamps 15 and 36 are not lighted to full brilliancy through the circuits just traced but are characteristically dimmed owing to e current being reduced by the resistance f the winding 56 of the thermal relay 55. After a.predetermined period, however, this 1 current produces suflicient heat in the winding 56 of the thermal relay to expand the member. 58 longitudinally 'to its contacts 57 thereby including a low resistance locking winding 59 of the thermal relay in bridge on its first winding 56. This reduction in the resistance of the lamp circuits permits additional current therethrough, and.v the illumination of the lamps 15 and 36 is now increased to full brilliancy', which constitutes a disconnect signal.

: In describing further characteristic sig' naling efiects on the. supervisory signals, attention is directed to that point in the foregoing-description at which a call had been, abandoned by a calling subscriber, at which moment the relays6, 12, 30, 40 and 61 are retained operated. The supervisory lamps .15 and 36 are only dimly lighted, and current action in .the Winding 56 of thermal relay 55 is taking place as. described. Now, in case the receiver is removedfrom the switch-hook at station 2, the supervisory relay 38 is operated-thereby completely extinguishing the supervisorylamp' 36 by the separation of contacts 37, and the super:

visory lamp 15is lighted at full brilliancy over the contacts 35.0f relay 38 to the earth connection, as the contacts 35' establish a short circuit through conductor 39, which embraces the Winding 56 of relay 55, con- .ductor 42,-contacts 46 of relay 45 and contacts .51 of relay 50. In case the switchhook is now intermittently operated at station 2, the supervisory lamp 15 [will flash from dim to full illumination, While the supervisory lamp 36 will flash from dim to entire absence of light. This flashing sig- 11211 is further distinctive in that the lamps respond in partially opposite phase. That is, when lamp 15 is brilliantly lighted, lamp 36 is entirely extinguished, both lamps beingdimmed at the same instant.

Let it be further assumed that the calling subscriber instead of the called subscriber,

- intermittently operates the switch-hook at lamp 36 is proportionately increased due to the ratio of current change in the winding.

56 of thermal relay 55, resulting from the cessation of current otherwise supplied through this winding from the circuit of the'lamp 15.- The lamp 15 is accordingly flashed from dim to being completely extinguished, While the lamp 36 is flashed. from dim to increased illumination. If, instead of the switch-hook being intermittently op erated at station 1, the receiver is retained off the switch-hook immediately aftera call has been abandoned, relay 40 will be restored due to theseparation of contacts 23 of supervisory relay 20. Contacts 41 of relay 40 now short-circuit the winding 56 of thethermal relay 55, thereby rendering each of the supervisory lamps 15 and 36 responsive to the respective line circuit with which the associated ends of the link circuit may be joined.

On completed connections, that is, When a called subscriber answers while the instrument is retained in the talking position at the calling station, the contacts ll of the relay 40 establish a short circuit on the wind ing 56 of the thermal relay 55, and each supervisory lamp l5 and 36 accordingly remain under the control of their respective supervisory relays 20 and 38. To briefly describe the operations which take place on such completed connections, let it be assumed that the operations of .a connection have been carried to the stage already described, as the moment before the calling subscriber abandoned the call. Accordingly, the relays 6, 12, 20, 30, 61, 40 and 45 would be energized. Now, when the call is answered by the removal of the receiver from the switch-hook at station 2, the increased quantity of ringing current, permitted through the winding of the trip relay 50 by the comparatively low resistance of the talking circuits at station 2, operates the relay 50, and the separation of its contacts 51 opens the circuits of the relays 40 and 45, thereby permitting these relays to restore. Separation of the contacts-47 of relay 45 prevents a reoperation of the relays 45 and 40 over the first circuit traced, and the separation of the contacts 23 of the supervisory relay 2O prevents the completion of the locking circuit, as previously traced, through the left hand winding of relay 40.

Talking battery is supplied to the instrument atstation2 through the windings of the supervisory relay 38. The condenser shown in each talking conductor of the link circuit is for the purpose of preventing interference between the answering and calling supervisory signals by separating the battery supply circuits of connected subscribers.

Although a thermally operated relay has been illustrated and described in this inventionTit will be understood that any form of mechanically retarded circuit-controlling device, dash-pot relay or similarly suitable device, may be substituted for the thermal relay Without departing from the purpose of this invention.

While a plurality of batteries have, for convenience, been shown in the drawing, such batteries may be and preferably are one and the same battery.

What is claimedis: 1. A telephone exchange system comprising a calling and a called telephone line, a link circuit connecting the lines, a supervisory signaling device for the link circuit, an operating circuit for the signaling device completed upon the restoration to the switchhook of the receiver at the calling station before the removal of the receiver from the switchhook at the called station thereby causing the signaling device to furnish a signal of one indication, and a cirergized thereby to cause the signaling device to furnish signals of one indication, and a circuit changing device for altering the condition of the operating circuit at the expiration of a predetermined period thereby causing the signaling device to furnish a signal of another indication.

3. A telephone exchange system comprising a calling and a called telephone line, a link circuit connecting the lines, a supervisory signaling device for the link circuit,

an operating circuit for the signaling de' vice completed upon the restoration to the switchhook of the receiver at the calling station before the receiver at the called station is removed from its switchhook thereby to cause the signaling device to furnish a signal of one indication, and a circuit changing switch for decreasing the resistance of the operating circuit at the expiration of a predetermined period thereby causing the 1 signaling device to furnish a signal of an other indication.

i. A telephone exchange system comprising a calling and a called telephone line, a link circuit connecting the lines, a supervisory relay for each end of the link circuit, a

signaling device controlled by each relay, an operating circuit for the signaling device completed upon the deenergizatio'n of an answering supervisory relay before the calling supervisory relay is energized, and a circuit changing switch for decreasing the resistance of the operating circuit atthe expiration of a predetermined period thereby causing the signaling device to furnish a signal of another indication.

5. A telephone exchange system comprising a calling and a called telephone line, a

link.v circuit connecting the lines, a supervisory signaling device for 'the link circuit,

an electrically operated circuit changing switch, an operating circuit for the signaling device including the circuit changing switch completed upon the restoration to the switchhook of the receiver at the calling station before the receiver at the called station has soryv relay for each end of the link circuit, a

signaling device controlled by each relay, an operating circuit for the signaling devices, a

I third relay when energized cooperating with the; supervisory relays when deenergized to complete the operating circuit through the signaling devices thereby causing said devices to furnish a signal of one indication, and a circuit changing switch subsequently operated to alter the condition of the operating-circuit thereby causing the signaling devices to furnish a signal of another indication.

7. In a telephone exchange system, a plurality of telephone stations, link circuits for interconnecting said telephone stations, supervisory signals for said link circuits, a

retarder circuit-controlling device for altering the character of the indications of said supervisory signals, and means, rendered operative when a call is abandoned by a calling subscriber, before the station called has answered, for rendering said retarder circuit-controlling device effective.

8. In a telephone exchange s stem, a plu- 'rality of telephone stations, li

circuits for interconnecting said telephone stations, supervisory signals for said link circuits, a retarder circuit-controlling device for altering the character of the indications of said supervisory signals, and means, responsive when the circuits at two connected telephone stations are in the talking position, for rendering said retarder circuit-controlling device inefiective;

9 In a telephone link circuit, supervisory signals, supervisory relays for controlling the operation of said supervisory signals, and a circuit-controlling means for simultaneously causing one of said supervisory signals to display a positive indication and another one ofsaid supervisory signals to display a negative signal in response to the operation of either one of said supervisory relays.

10. In a telephone link circuit, supervisory lamps, supervisory relays for controllin the operation of said supervisorylam'ps, an a circuit-controlling means for control-. ling said supervisory lamps to be dimly lighted for one position of either one of said supervisory relays and to cause one of said supervisory lamps to bebrilliantly lighted in synchronism with the extinguishing of the other one of said supervisory lamps for the other position of either one of said supervisory relays. I f

'11. In a telephone link circuit, supervisory lamps, supervisory relays for controlling the.

operation of said supervisory lamps, a circuit-controlling means for effecting said supervisory lamp to be dimly li hted for one position of either one of sai supervisory relays and to cause one of said supervisory lamps to be brilliantly lighted in synchro nism with the extinguishing of the other one of said supervisory lamps for the other position of either one of said supervisory relays, and a slow-acting relay cooperatin with said circuit-controlling means and sai supervisory relays to control such characteristic indications of said supervisory lamps. In witness whereof, I hereunto subscri e my name this 16th day ofOctober, A. D.

HENRY P. OLAUSEN. 

